Carbon atom insertion bicycloannulation: total syntheses of ishwarane and ishwarone
作者:Robert M. Cory、Lester P. J. Burton、Dominic M. T. Chan、Fred R. McLaren、Mary H. Rastall、Richard M. Renneboog
DOI:10.1139/v84-328
日期:1984.10.1
methyllithium at low temperatures. This new bicycloannulation method has been employed in a total synthesis of ishwarane (1), the naturally occurring parent hydrocarbon of the ishwarane class of tetracyclic sesquiterpenes. Although this reaction was not successful with various possible precursors of ishwarone (2), this natural product was prepared in low yield by a two-step version of the carbon atom
将碳原子插入甲基环己烯,通过卡宾加成到双键和卡宾插入甲基 CH 键,在单一合成步骤中生成双环 [3.2.1.02.7] 辛烷,已通过处理环己烯与四溴化碳和甲基锂在低温下。这种新的双环环化方法已用于 ishwarane (1) 的全合成,这是 ishwarane 类四环倍半萜的天然母烃。尽管该反应对 ishwarone (2) 的各种可能的前体都没有成功,这种天然产物是通过碳原子插入双环环化 (CAIB) 程序的两步形式以低产率制备的,该程序包括将溴仿衍生的二溴卡宾添加到辛酮 (5) 中,然后用甲基锂处理所得的二溴环丙烷 (56)。同样的两步序列也成功地用于 Norishwarane (20) 的第一次合成,该碳氢化合物包含裸...